Be smart & save money. Your rims are just scratched up (wait till you see what happens after she parks it at the high school parking lot.)
Keep the rims, take them too a GOOD mechanic and buy tires from him (reminding him that you can also get them through TireRack so he discounts what he offers. I just did this and my mechanic told me all professional mechanics are aligned with a tire distributor. Gave me Pirelli Scorpions at the TireRack price. (Plus refinished the rims.)
) Have him refinish the rims to stop the leaks (its not hard to refinish rims to stop leaking, plus they can always use a sealer, either way, stops leaks.)
Tires..? I'm a firm believer in GOOD tires, not (never) cheap. I like Pirelli Scorpion's.
BTW, 21's weren't listed as an OEM size (18" & 20"). 22's were listed as optional.
One more thing, don't forget to check the spare. They have a habit of losing air or valve stem cracking from age.